In many surgical procedures, it is often necessary to ligate a plurality of vessels within the surgical site. The vessels may then be severed downstream of the ligated portion. In some instances, the vessel may be ligated at two areas, spaced from one another, and the portion of the vessel between the ligations removed. The primary reason for ligating the vessels is to maintain the surgical site free of an excess of blood and to reduce blood loss in the patient. Also in certain surgical procedures wherein tumors or parts of organs and the like are to be removed, the tumor or organ may have to be separated from certain vessels which before separation, will have to be ligated.
Once a blood vessel is completely shut off, hemostasis; that is, the natural closing of the ligated end of the vessel so as to stop blood flow, will occur in about 3 to 5 days. The body, in the meantime, will continue to allow blood to flow around the ligated area through appropriate capillaries and secondary vessels. The natural physiological functions of the body eventually enlarge these by-pass vessels until adequate blood flow is attained. Hence, when ligating the vessel, there should be a positive stopping of the blood flow in the main vessel; i.e., no leakage, which might cause blood loss in the patient and may disrupt the natural hemostasis and concurrent manufacture of new paths of blood flow in the patient.
In the past, this closing of the vessel was usually accomplished using ligatures; i.e., threads or filaments which the surgeon tied around the vessel desired to be closed. This is a very time-consuming process and one in which positive closure of the vessel was not always accomplished.
In relatively recent years, hemostatic clips have replaced the ligatures in many surgical procedures to close blood vessels and other small fluid ducts. These hemostatic clips have been narrow U-shaped or V-shaped strips formed of tantalum or stainless steel which are capable of being deformed and possess sufficient strength to retain the deformation when clamped about a blood vessel. The clips are generally applied using a forceps-type device having jaws channeled or otherwise adapted to hold the open clip. Representative hemostatic clips and appliers of the prior art are best illustrated in U.S. Pat. Nos. 3,867,944; 3,631,707; 3,439,523; 3,439,522; 3,363,628; 3,312,216; and 3,270,745.
Although the metal hemostatic clips are relatively easy to apply and accomplish a positive closing of the vessel, the metal devices are expensive to manufacture and perhaps more importantly disrupt post operative X-ray procedures and future diagnostic imaging procedures. Hence, it is desired that hemostatic clips be made from materials which will not disrupt the post-operative or other future diagnostic procedures, such as X-ray imaging, computerized axial tomography imaging, and the like.
It is critical that hemostatic clips used in surgery be sterilizable by the well known sterilizing techniques; such as, ethylene oxide treatment, cobalt irradiation, and the like without loss in functionality of the clip.
It has been suggested in the prior art, as in U.S. Pat. No. 3,439,523, for example, that hemostatic clips might be formed of inexpensive plastics or materials which are slowly absorbable in the body. Unfortunately, conventional U and V-shaped hemostatic clips do not possess the required strength or deformability when constructed of known plastic materials to be successfully clamped about a blood vessel. Thus, although the need and desirability of providing inexpensive, non-metallic, bio-compatible ligating clips of both absorbable and non-absorbable materials has been recognized for over ten years, there has been no practical way to satisfy this need.
To accomplish the positive closing of the vessel with non-metallic, bio-compatible hemostatic clips, the vessel clamping surfaces of the clips should have substantially no gap between the surfaces when the clip is closed. Also, the surfaces should be sufficiently smooth and have large enough areas so as not to sever or even partially sever the closed vessel. The non-metallic hemostatic clip, once placed in a clamping position on a vessel, must maintain that position for the period of time required for hemostasis to take place. The clip must maintain its strength in vivo to withstand the pressure trying to force the vessel back open for a sufficient period of time to allow for the natural permanent shutting of the vessel.
The configuration of a hemostatic clip is also important. Because the clip is often used in and around the important organs of the body and the clip is left in the body after the surgical procedure is completed, it is important that the clip be configured to keep trauma within the area; i.e., irritation from a foreign object, to a minimum. Smoothness and size of the clip as well as a lack of projections and a minimum of sharp angles all contribute to reducing the trauma which may occur when placing a foreign object such as a hemostatic clip, within a human body.
The clip configuration is also important to insure the proper placement of a clip. When hemostatic clips are used in a surgical procedure, the general practice is for the nurse to pick up the clip in the jaws of a forceps type applying instrument. The nurse passes the instrument with the clip in place to the surgeon. The surgeon places the jaws of the instrument into the surgical site and around the vessel to be ligated. In many instances, the surgeon will be placing the jaws of the instrument into areas where the surgeon has very limited vision. The surgeon then closes the clip over the vessel to be ligated. All of the handling and manipulation of the instrument must be accomplished without dropping the clip and while maintaining the sterility of the clip.
The size of the clip is also important as the smaller the clip, the less foreign material there is being implanted in the patient. Also, the smaller size allows for more clips to be used in a surgical procedure and in certain instances may simplify the procedure or at least reduce possible side effects resulting from the insertion of foreign objects within the human body.
U.S. Pat. No. 3,926,195 describes a small, plastic clip designed for the temporary or permanent closure of the oviduct and vas deferens in humans. These clips preferably have a clamping surface of from 6 to 10 mm in length and 3 to 6 mm in width. The size of such clips are accordingly considerably larger than is desirable for hemostatic clips. Additionally, clips of U.S. Pat. No. 3,926,195 require the use of several complex tools to apply the clips which are acceptable for the purposes described in the reference but would be unacceptable in a surgical procedure requiring the rapid placement of a large number of hemostatic clips to stem the flow of blood from severed vessels.
In commonly assigned co-pending patent applications Ser. Nos. 49,376 and 49,379 filed June 18, 1979, there are disclosed several configurations of hemostatic clips which possess the advantages and characteristics described herein. Although these clips are especially suitable for surgical procedures, the hinge area in the clips described may, in certain instances, break. This may occur either as the clip is closed or after the clip has been applied to a vessel. Breakage occurs at the hinge area because of the higher stresses found in that area. Though this is an extremely rare occurrence, provided the clips are manufactured correctly and not abused when they are being applied, nevertheless, the closing of the clip and the maintenance of the closed clip is not absolute or foolproof.
Furthermore, in many surgical procedures, it may be desirable to use clips made from an absorbable polymer. Clips made from absorbable polymers have the advantage of not disrupting subsequent X-ray imaging, CAT scanning and the like. Such clips have the added advantage of being totally removed or hydrolyzed by the round physiological functions of the body. However, because of the thinness of the hinge area of the clip and the high stresses in that area, the hinge will be hydrolyzed before the rest of the clip. If the hinge area is hydrolyzed too soon and the clip breaks at that area, the clip will not have performed its desired function.
Also in the design of the clips shown in the prior art, if the hinge area is made too strong and not sufficiently resilient, the closing of the clip may leave a gap immediately adjacent the hinge area which may, in certain instances, be sufficient to prevent the complete closing of a vessel.
While the importance of the clip to the surgical procedure has been discussed, it should be pointed out that the configuration of the clip is also important to the manufacture of the clip. The configuration should be such as to take advantage of simple and economic means of manufacture of the clip such as injection molding. The configuration should be such as to reduce the production of seconds or malformed clips during manufacture. Also, the configuration of the clip should be such as to allow for very simple design of the jaws of the applier to reduce cost of the applier while maintaining the required assurance of holding and setting the clip during the surgical procedure.
It is accordingly an object of the present invention to provide a non-metallic, bio-compatible, hemostatic clip effective for clamping off small blood vessels and other fluid ducts in the body. It is a further object of this invention to provide hemostatic clips of both absorbable and non-absorbable materials. It is yet a further object of this invention to provide non-metallic, bio-compatible hemostatic clips which are quickly and easily applied to severed blood vessels and other fluid ducts with a single forceps-type instrument used in applying metallic clips.